1. Field of the Invention
This invention relates to a polymerization process initiated by selected organo-silicon, -germanium and -tin compounds, and to "living" polymers therefrom.
2. Background
Preparation of "living" polymers by Group Transfer Polymerization (Webster et al., "Group Transfer Polymerization--A New and Versatile Kind of Addition Polymerization", J. Am. Chem. Soc., 105, 5706 (1983)) is well known. Group Transfer Polymerization (GTP) methods are described in U.S. Pat. Nos. 4,414,372; 4,417,034; 4,508,880; 4,524,196; 4,581,428; 4,588,795; 4,598,161; 4,605,716; 4,622,372; 4,656,233; 4,659,782; 4,659,783; and 4,681,918; and in commonly assigned U.S. patent application Ser. Nos. 660,588 filed Oct. 18, 1984 now U.S. Pat. No. 4,711,942; 912,117 now abandoned and 912,118 now U.S. Pat. No. 4,732,9 both filed Sept. 29, 1986; 934,826 filed Nov. 25, 1986 now U.S. Pat. No. 4,783,500; 004,831 filed Jan. 13, 1987 now U.S. Pat. No. 4,822,859; 007,758 filed Jan. 27, 1987 now U.S. Pat. No. 4,806,605; and 048,958 filed May 19, 1987 now abandoned. These patents and patent applications disclose processes for polymerizing an acrylic or maleimide monomer to a "living" polymer in the presence of:
(i) an initiator having at least one initiating site and which is a tetracoordinate organo(Si, Sn or Ge) compound, including such a compound having at least one oxygen, nitrogen or sulfur atom attached to Si, Sn or Ge; and
(ii) a co-catalyst which is a source of fluoride, bifluoride, cyanide or azide ions or a suitable Lewis acid, Lewis base or selected oxyanion.
The aforesaid patents and patent applications also disclose capped, block, star and graft polymers prepared by GTP methods, and any of such polymers containing functional groups which are useful for further processing Group Transfer Polymerization is further discussed in detail by Sogah et al. in Macromolecules, 20, 1473 (1987).
It is an object of this invention to provide additional initiators, that is, in addition to those disclosed in the aforesaid patents and patent applications, for use in Group Transfer Polymerization. Another object is to provide "living" polymers which are prepared through use of the additional initiators, which "living" polymers include residual moieties of the initiators in their polymer chains. These and other objects will become apparent from the following description of the invention.